1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. In addition, the present invention relates to a process, a machine, manufacture, or a composition of matter. One embodiment of the present invention particularly relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a driving method thereof, or a manufacturing method thereof. One embodiment of the present invention particularly relates to a light-emitting device in which a transistor is provided in each pixel.
2. Description of the Related Art
In an active matrix light-emitting device including light-emitting elements, when the threshold voltages of transistors for controlling the value of current supplied to the light-emitting elements in accordance with image signals (such transistors are also referred to as driving transistors) vary, the luminances of the light-emitting elements vary accordingly. As a means for preventing the variation in luminance among the light-emitting elements due to the variation in threshold voltage, a display device which corrects, inside pixels, variation in luminance among the light-emitting elements due to variations in threshold voltage and mobility is disclosed in Patent Document 1. Patent Document 2 discloses a display device which determines threshold voltage and mobility from a source voltage of a driving transistor and sets a program data signal based on the determined threshold voltage and mobility depending on a display image.